Vibrator



1939. E. 1., BARRETi' 2,156,487

VIBRATOR Filed Oct. 10, 1958 Patented May 2, 1939.

UNITED STATES PATENT OFFiCE VIBRATOR Application October 10, 1938,Serial No. 234,187

16 Claims.

The invention relates to improvements in vibrators or vibratory motorsof the general type disclosed in Edward L. Barrett Patent No. 1,924,082issued August 22, 1933. Such vibrators 5 are utilized in so-calledB-battery eliminators for radio receiving sets. These eliminator-s servein general to convert low voltage direct current, such as that derivedfrom a conventional 6 volt automobile storage battery, into highpotential direct current of, for example, 200 volts, suitable for use insupplying the plate circuits of the vacuum tubes in a radio receiver.The primary function of the vibrator is to break up direct current fromthe low voltage source into a series of short rapid impulses which arecaused to flow through the primary winding of a step-up transformer.These impulses of current in the primary winding induce a highalternating potential in the transformer secondary winding. This highalternating potential is then rectified by some suitable meanscomprising either a rectifier tube, as illustrated in said Barrettpatent, or rectifier contacts in the vibrator itself. Vibrators whichserve only to interrupt the primary current are commonly;

lrnown in the art as "non-synchronous vibrators while those thatadditionally serve to rectify the secondary potential as well arecommonly known as synchronous vibrators. The present invention, likethat of said Barrett patent, is applicable to either synchronous ornon-synchronous vibrators,

y The vibrator of said Barrett patent is particularly adapted to meetthe exigencies of use in automobile installations, in that it is notaflected materially in operation either by the effects of gravity, dueto different positionings of it, or by wide changes in value of the lowpotential source 4 vibrator in which the electromagnet' is so placedoutside of the reed path, although others of such 50 improvements arealso applicable to vibrators of the so-called hammer type in which amovable armature swings directly toward rather than past the cooperatingelectromagnet pole-piece. I

One general object of the present invention is to provide a vibrator soconstructed as to reduce the cost of production materially as comparedto the prior forms. In fact, a saving of nearly 30% to 40% in cost ismade by utilizing the construction herein disclosed as compared to themost economical construction heretofore available. A

number of factors in the novel vibrator construcv tion herein disclosedcontribute to the achievement of this result. Among these factors are:(a) the use of a frame so fashioned as to constitute a jig forassembling at least a portion of the other vibrator parts as well as toconstitute a support therefor upon the completion of the unit; (b) theuse of a frame made of insulating material and so arranged that aminimum number of other pieces are required to complete the assembly orassemblies secured to it including the contact structures andcooperating reed; (c) the use of a magnet coil which is adapted to bewound in place on the assembly rather than being fashioned as'apreformed coil; (11) the provision of a vibrator structure such that itcan be readily slipped into a test fixture, with an action much likethat of plugging in a lamp, for initial testing before the usualconnecting wires are soldered to it and the device enclosed in its soundinsulating casing; and (e) the use of a bare wire lead or leadsprotected by a dielectric frame for the device "rather than lead wireswrapped with insulation.

Another general object of the invention is to provide a vibrator havingimproved operating characteristics and particularly,- a more efllcientmagnetic circuit for the electromagnet' and cooperating reed carriedarmature, as well as a diminution in mechanical noise during operation.

Further objects and advantages of the invention will become apparent asthe following descrlptionproceeds, taken in connection with theaccompanying drawing in which:

Figure 1 is a side elevation of a vibrator unit I embodying theinvention, with the sound insulating casing therefor shown in verticalsection.

Fig. 2 is an exploded perspective view of the vibrator oi. Fig. 1.

Fig; 3 is an enlarged front elevation of the device of Fig. 1 with theenclosed casing shown in vertical section and the upper end portionthereof broken away. y

Fig. 4 is an enlarged transverse sectional view along the line 4-4 inFig. 1.

tional view along the line 55 in Fi 1.

Fig. 6 is a wiring diagram of the connections of the vibrator and itsassociated elements.

Fig. 5 is an enlarged fragmentary vertical sec- Por purposes ofillustration the invention has been shown.herein as embodied in" avibrator particularly adapted for use in an automobile radioreceivingset. It will be understood, however, that this vibrator is also adaptedfor use in other types of installations. Furthermore, the particularvibrator shown is of the non-synchronous type, although it will beapparent that additional contacts may be added to complete a synchronousvibrator construction if desired. In I general, the vibrator illustratedincludes two pairs of main circuit controlling make and break contactsl0ll and l2 -l3 operated by a substah- O tially freely-vibratory reed H,which is driven by an actuating electromagnet IS.

The various parts of the vibrator are assembled on a framepreferably'made of molded di-' electric material and designated hereingenerally by the numeral l6. Various suitable moldable insulatingcompounds are available on the market from which the frame may be made.For example, it may be molded from a phenolic condensation productcommonly known as Bakelite and having asbestos mixed with it. This ma--terial forms a strong rigid structure which is not subject to warpagewhen heated. The preferred frame l6 shown herein (Fig. 2) is of aC-shape and embodies an elongated side member I'I, having an integraland laterally facing pedestal l8 fashioned on its lower end. The secondor upper arm IQ of the'C-shaped frame has fiat inner and outer faces andconstitutes a spool end for the energizing winding of the electromagnetI5.

The reed I4 is of the cantilever type and is adapted to flexsubstantially throughout its,

length, being preferably made from a flat strip of spring steel orbronze. Except for its butt end portion, the reed I4 is of the samegeneral form as that included in the vibrator which is disclosed inEdward L. Barrett et a1. Patent No. 2,072,578issued March 2, 1937. Inparticular; an elongated opening is formedin the center of the reed inorder to give it certain pre-- ferred flexing characteristics and alsoto insure unimpeded flexure of the reed despite the multiplicity ofassociated contacts. The opening 20 increases in width adjacent theouter end of the reed; thereby providing substantially uniform flexureto the outer end, with a consequently greater time emciency for' thevibrator. A rectangular armature 2| made of steel or othermagnetizable'materlal is spot welded or otherwise rigidly secured to.the free end of the reed. This armature is disposed in driven relationwith respect to the pole pieces of the electromagnet l5 as ishereinafter described in greater detail. In its idle position the reedl4 occupies a substantially straight line position (Fig. 1) and in whichboth of the pairs of the main make and break contacts [0-H and l2l3 areopen. Upon vibration of the reed the pairs of contacts will bealternately closed and opened. For this pur-- posethe contacts I I andI2 are carried by contact supportingfingers 22 and 23 (Fig. 2) of aninverted T-shape with the heads of the T riveted to the side portions ofthereed J4. upwardly extending legs of the fingers 22-43 Thearebent-laterally out of the plane of the reed. The cooperating fixed orstationary contacts I 0 and I3 are, in turn, carried by contact fingers24 and 25, preferably fashioned as stampings from resilient sheet metal,the c ontactsupports 24- and 25 being substantially identical in form.All of the contact points ll to l3 may be made of tungsten or othersuitable contact. material.

The reed I4 and opposed side contact fingers 24 and 25 are heldinassembled relation on the pedestal l8 of the frame It in a so-calledstack. In this stack electrical insulators or laminations 26 areinterposed between the reed and the contact supporting fingers on itsopposite sides. Ad-

ditionally the stack includes metal spacers or laminations 21 and 28, aswell as ametal end plate or spacer 29. Laterally extending lugs 21'arefashioned on the side of the spacer 2b in order to complete anelectric. circuit to the reed and through it to the contacts I l and I2.Registering holes 30 are formed in all of the stack parts as well as inthe pedestal 18 of the frame so that the stack may be held in positionby a screw 3| inserted through them and threaded in a nut 32. The holes30 in the intermediate metal parts in the stack, i. e., the reed l4,fingers 24-25 and spacers 2'I28, are made larger in diameter than theholes in the other parts so that these inter.- mediate metal parts willnot contact the screw 3|. To prevent displacement of the screw 3|, alock washer 33 is utilized and the outer end of the hole 30 in the framepedestal I8 is made hexagonal in form to receive the complementallyshaped nut 32.

Simplicity in assembly 6f the stack parts destack parts since some ofthese, such as the contact supports 24 and 25 as well as the reed l4,must be maintained insulated from each other. Consequently, theprojections 34 are preferably made integral with the frame l6 if thelatter is molded from dielectric material, as is herein shown. Theprojections could be in the form of insulating pins secured to a metalframe but the use of integral insulating projections on. a frame whichis also fashioned from insulating material is in itself desirable forseveral additional reasons. For one thing, the projections 34 serve todetermine at least approximately the longitudinal location of the reedl4 on the frame and since this is a very critical relation it isdesirable that integrally formed projections be used so that therewillbe no possibility of error due to inaccuracy in their location. Asto the function of the projections 34 in determining the longitudinallocation of the reed l4, the position of .the reed in this respect mustbe very precisely determined because of the extremely small clearancewhich is provided between the end of the armature 2| and the cooperatingelectromagnetic pole piece or pole pieces. .In a vibrator constructionsuch as that illustrated, in whichthe armature swings past rather thantoward the active face of the electromagneticpole piece, it is desirablethat the clearance between these parts be of the -order of about 0.003of an inch. Such asmall clearance necessitates very precise positioningof the reed, especially in view of the fact that if the armature rubseven slightly against the pole piece the device is rendered entirelyinoperative and, on the other hand, if the clearance materiallyincreased the emciency of the electromagnetic circuit is materiallyimpaired.

One suitable method of assembling the parts described is to dimensionthe notches in the butt of the reed l4 so that they have about 0.004inch clearance with respect to the projections in so far as endwisemovement of the reed is concerned but with practically no clearance fortransverse shifting of the reed. When the parts are so dimensioned, thestack can be assembled by placing the lamination parts on the frame inproper order and then the screw 3| partially tightened to hold the partsloosely in place. Thereafter, a thin sheet metal gauge may be insertedbetween the outer endface of the armature 2| and the opposedelectromagnetic pole piece face and the reed pushed longitudinallytoward the electromagnetic pole piece until the gauge is firmly pressedbetween the opposed faces. While the reed is in such position the screw3| is tightened so as to hold the reed firmly against subsequentdisplacement. This general mode of assembly is described and claimed inBarrett Patent No. 2,121,851 issued June 28, 1938.

Proper location of the electromagnet I5 on the supporting frame I6 ischeaply and effectively insured by embedding a central pole piece orcore of the electromagnet (Fig. 2) in the frame structure during theinitial molding of the latter. The pole piece 35 is made of steel orother mag- ,netizable material and is preferably in the form of a pin ofhexagonal cross section. Dislodgment of the pole piece 35 from the framearm is is prevented by notching the lower end of the pole piece, asindicated at 36 (Fig. 5) so that the plastic material which makes up theframe fiows into the notch during the initial molding operation. Theinner end face of the pole piece 35 is flush with the face of the framearm is and is located very close to, although entirely outside of thepath of movement of the free end of the reed M which carries thearmature 2i.

An outer spool end for the electromagnetic winding, cooperating with theopposed inner spool and formed by the frame arm i9, is shown herein(Figs. 2 and 5) as a washer 31 of insulating material which is fitted onthe shouldered outer end of the pole piece 35. Between these spool endsa coil of wire 38 is wound or spooled and finally covered with a layerof insulating paper so as to form an actuating winding for energizingthe pole piece 35.

From the foregoing, it will be apparent that the winding 38 can bereadily formed in place on the core 35 by, for example, placing theframe l6 and attached pole piece 35 in a winding machine and winding thewire on the pole piece or 75 fines of the frame also makes it possibleto shift pin 35. This obviates the necessity of fashioning a preformedcoil with its necessary inner spool and attaching sleeve (such, forexample, as the spool 31 and sleeve 25, shown in Fig. 5 of sa d Barrettet al. Patent No. 2.072578) and also dispenses with the labor and timerequired for adjusting and assembling such parts. Besides the advantageof winding the coil in place on the vibrator rather than preforming it,other advantages accrue from the use of an electromagnetic structurelocated largely outside of the confines of the supporting frame. For onething, the length of the member I! of the frame is shortened withconsequent increase in rigidity as compared, for example, to the lengthof the side arms I I of the frame I 0, shown in Fig. 5 of said Barrettet al. Patent No. 2,072,578. Rigidity of the frame is, of course. aprime requisite in vibrator structures since the reed itself ordinarilyvibrates at a rate of at least 100 cycles per second and if theassociated structure is such that sympathetic or secondary vibrationscan be set up in it, the operation of the device is likely to beimpaired. Location of the electromagnet I 5 outside the contheelectromagnet to, the left (as viewed in Fig. 1) away from the centerline of the reed M with out increasing the over-all width of thevibrator but with an improvement in the electromagnetic circuitarrangement, as will hereinafter appear. This location of the pole piece35 close to the juncture of the frame parts ll and i9 also insures aminimum displacement of the pole piece in the event that the frame arml3 should warp.

The magnetic circuit for the electromagnet I5 is completed by polepieces located at the ends of the armature 2i and shown herein as formedby the arms 39 (Figs. 2 and 5) on a metal stamping 40. These arms 39constitute a part of a generally U-shaped portion of the stamping 40,which embraces the winding 3%. This stamping 40 is held in position onthe outer end of the core pole piece 35 which is inserted through thehole M and spun or peened over as indicated at 42 (Fig. 5). The stampingAll is made of magnetizable material such as cold rolled steel. Tofurther hold the stamping (iii in position the arms 39 are inserted inregistering notches :33 (Fig. 2) in the side edges of the frame arm it.Preferably, the arms 39 are tensioned inwardly toward each otherslightly so that when the stamping iii is slipped into place the arms 33will be spread apart slightly by the frame part 59, and that wayaccurately spaced apart a precise distance. The width of the moldedframe part it between the bottoms of the notches :53 is fixed by a diedimension in the mold rather than a mold dimension" so that it is alwaysprecise. Upon reference to Figs. 4 and 5, it will be seen that the polepiece 35 is located centrally between the side pole pieces 39 and thatthe ends of the latter project outwardly beyond the face of the polepiece 35. Furthermore, the upper edges of the pole pieces 39 projectslightly above the flat upper edge of the face of the pole piece 35 (seeparticularly Fig. 4). ture H is disposed with its inner facesubstantially in alinement with the edges of the pole pieces 39 and withits ends closely spaced with respect to them. Such an arrangement ofparts insures a strong magnetic pull on the armature both-at startingand during operation. In fact, with the construction illustrated it hasbeen found that the same number of ampere-turns in the energizingwinding 38 produces, in a reed with the same flexing characteristics. asubstantially larger amplitude of swing for the reed and armature thanin any vibrators heretofore available.

In an analysis of the magnetic circuit. it will be seen that in theabsenceof the armature ill the normal magnetic flux path would bedirectly between the inner end of the pole piece or core 35 and theadjacent outer end portions of the pole pieces 39. In its idle positionthe armature 2i is located eccentrically with respect to this line offlux fiow so that whenever the electromagnet is energized there is atendency to pull the armature 24 to the left (as viewed in Figs. 1 and4) to a pos tion in which it bridges directly between the central polepiece 35 and the side pole pieces 39. Furthermore, when the armature 2|is in its normal or idle position, as illustrated, the reluctance of themagnetic path established 'by it between the pole pieces is quite lowsince all of the air gaps are small and, consequently,

Also, in its idle position the armaa large amount of magnetic fiux linksthe armain the iron circuit, namely, that between the armature and core35 is also very small. Furthermore, the core 35, due to its hexagonalshape, presents a relatively long edge to the armature and through whichthe magnetic flux may be distributed as distinguished from the greaterconcentration of flux resulting if, say, a round core were used. Suchconcentration is, of course, undesirable since it chokes the flow of themagnetic flux. It is noteworthy that the eccentric disposition of themagnetic field with respect to the armature is achieved without thenecessity of cutting away or notching the end of the central pole piece35 .as has been coonlydone in many prior vibrators. This is possiblesince, in the present vibrator, the entire magnetic structure can, dueto the mounting'of such structure exteriorly of the confines of theframe, be shifted off center with respect to the reed and armaturewithout increasing the over-all width of the device.

1 In a vibrator the actuating electromagnet is periodically energized byelectric current supplied under the control of the vibrating reed sothat the latter will be maintained in vibration at a predeterminedfrequency, which depends largely upon the inherent flexingcharacteristics or natural frequency of the reed. Several circuitarrangements are available for controlling the energization ofthe-electromagnet in thisgeneral manner, one of these being illustratedin Barrett Patent No. 1,924,082, referred to above, and in which theelectromagnet circuit is controlled through the medium of the maininterrupting contacts in the vibrator. Another arrangement is describedin Edward L. Barrett Patent No.

2,120,273, issued June 14, 1938, and in which a separate set of magnetcontrolling contacts are utilized for periodically interrupting the flowof -current to the electromagnet. The latter form of electromagnetcontrol has been embodied in the present vibrator, although it will beapparent to those skilled in the art that, if desired, the vibratorherein shown may be built without any separate magnet controllingcontacts and the main interrupting contacts used for that purpose in themanner disclosed in said Barrett Patent No. 1,924,082.

In the preferred construction herein illustrated, the electromagnetenergizing winding 38 is connected in serieswith a pair of, magnetcontrolling contacts 45 and 46 (Fig. 1) which are respectively carriedby the reed and stationarily mounted at the side of it, these contactsbeing normally closed in the idle position of the reed l4. Uponreference to Figs. 1 arm 2, it will be seen that the contact point 45 isfixed to the outer end of an extension 23 on the contactsupporting'finger 23, while the contact point '46 is carried by anelongated resilient spring finger 41. The finger 41 is bent toward thereed l4 and is carried by a complementally shaped, integral finger orprojection 48 on the stamping 40, being held in position thereon byclamp plate 49 and rivets 50. When using such a separate set of contactsfor controlling the electromagnet winding the arcing at these contactsis preferably minimized by using a winding made up of conductivelysheathed wire as described and claimed in said Barrett Patent No.2,120,273.. For example, the wire of the winding 30 may be covered witha coating of insulating enamel or the like and then a conductive sheathformed on the outside of this insulating coating by dipping the wire ina silver nitrate solution such as is used for platto above.

'brator.

ing mirrors. This conductive sheath is connected to one terminal of thewinding (Fig. 6).

An insulating support for a lead wire 88 from the magnet coil 38 isformed by one of the grooves i! in the outer side of the frame l8 (Fig.4). 5 The other terminal of the winding 38 is soldered to the metalstamping). By utilizing the dielectric frame it to receive the lead wire38, a bare wire can be used, thereby saving the cost of insulatingtubing for the same. 9 Additional y, the ooves il in the frame it serveto define strengthening ribs in-it.

That a substantially smaller number of parts are required in thevibrator described above than in devices of comparable high qualityheretofore available will be readily apparent from'a chmparison of Fig.2 herein with, for example, Fig. 5 of Barrett et al. Patent No.2,072,578 referred In the vibrator of the latter patent eleven parts areincluded in the stack, exclusive of the reed and frame, while in thepresent vibrator only seven such parts are required. Even thiscomparison is unfair to the present vibrator since the device in Fig. 5of said Barrett et a1. patent does not include any separate magnetcontrolling contacts. A fairer comparison would be that of the vibratorshown in Fig. 3 of said Barrett Patent No, 2,120,273 and in which itwill be seen that the stack includes fifteen parts exclusive of the reedand frame.

There is a manifest saving in cost of production due to lower cost ofmaterials with the smaller number of parts required in the present vi- Afurther saving results when such a smaller number of parts are used dueto the fact that the time and labor required in assembly of the deviceand inspection of the assembly are less.

An important saving in the cost of assembly is also accomplished byvirtue of the utilization of a frame structure which, in itself,constitutes an assembly jig for the stack parts in the manner heretoforedescribed. When using such self-alining, inter-fitting parts in thevibrator it is "unnecessary to provide an assembly jig or tool,

winding is completed the stamping 40 is fixed in position, the contactpoint finger 41 and clamping plate 49 having been previously aflixed tothe stamping 40 by the rivets 50. The laminations or parts included ,inthe stack (shown in Fig. 2)

are dropped in proper order on the face of the.

frame pedestal l8 and are'automatically alined in-position by the lugs34. This may be done either before or after affixing the stamping 4!.The screw 3| is then inserted in the registering holes 30 and partiallytightened, after which the reed I4 is gauged to its proper position aswas heretofore described and the screw 3| then finally tightened down.

Itwill be appreciated that the lugs 34 aid not only in the assemblyoperation, but also prevent twisting of the stack parts about the axisof the screw 3|. By reason of this action it is unnecessary toprovidetwo or more screws for the stack as in many previousconstructions and, furthermore, the screw 3| may be made larger indiameter than was heretofore advisable so that there is less likelihoodof its being bent and thereby distorting the position of parts in thestack. 0

A preliminary testing of the vibrator is desirable before it is finallyput in its enclosing case since, when it is in the latter it isconnected by soldered lead wires to its usual plug type mounting base.Consequently, if the vibrator does not operate properly after it hasbeen fixed in position within v the enclosing case it is necessary tounsolder the connections, thereby wasting much time and effort in thedisassembly of the enclosing structure to determine the source oftrouble. In the present vibrator structure provision has been made for apreliminary operating test of the device which does not require that anylead wires or the like be soldered or otherwise fixedly connected to thevibrator parts. In particular, lugs 24*- and 25 have been fashioned onthe sides of the contact fingers 24 and 25, respectively, and the lugs21 extend laterally from the sides of the spacer 21, which contacts thebutt end portion of the reed I4 (Fig. 2). The lugs 24 and 25 are bentlaterally away from each other and are disposed above the lugs 21 sothat there is a substantial separation between all of them.Consequently, the lower or butt end of the vibrator may be readilyinserted into a test receptacle (not shown) having spring contactstherein arranged to engage the respective lugs so as to complete testingcircuits to the vibrator. Consequently, the manipulations necessary forsetting up the vibrator for test are as simple as merely plugging in alamp or the like. During the preliminary test the operation of thevibrator can be observed and if any adjustments are necessary they canbe readily made since all of the parts are still fully accessible.

After being preliminarily tested the vibrator may be conveniently placedwithin the sound insulating enclosing case herein shown. This enclosingstructure embodies a cup-shaped sock 5| made of sponge rubber or thelike, (Figs. 1 and 3) which is open at its upper end to receive thevibrator and has a complemental recess 52 in its base shaped to receivethe lower end of the vibrator assembly. The side walls of the recess 52are notched as indicated at 53 (Fig. 3) to receive the side lugs 24', 25and 21* on the stack. In this way the side lugs perform an additionalfunction of holding the vibrator assembly against endwise displacementwithin the sock 5|, especially when the device is turned upside down ortilted in some such manner.

The base of the sock 5! fits snugly about the stack on the lower end ofthe vibrator assembly so that sidewise tilting is effectively prevented.It should also be particularly noted that the sock resiliently grips thevibrator assembly in a region close to its nodal point so that a minimumamount of vibration is transmitted from the vibrator to the sock. Theupper end of the sock is closed by a disk 54 (Fig. 1) of sponge rubberor the like which is pressed in position after the vibrator is insertedinto the interior of the sock. A cupshaped metal can or casing 55,closed at its upper end, is telescoped overthe sock or liner 5| and fitssnugly about it. The side walls of the sock are cut away as indicated at56 (Figs. 1, 3 and 4) so that peripheral contact is established betweenthe sock 5i and the inner walls of the can only at the base portion ofthe sock and at its extreme upper end. In this way the principal contactbetween the sock and enclosing casing is established in'the region ofthe nodal point of the vibrator structure so that again a minimum amountof mechanical vibration is transmitted to the exterior can structure.

The lower end of the can is closed by a cap 51 which holds in place adisk of insulating material 58 on which are mounted the usual hollowconnecting prongs 59. Lead wires 68 from the terminal lugs 24 and 2'! inthe stack are soldered to these lugs and to the lower ends of the prongs59. These wires are led through suitable apertures in the base of thesock 5| and are insulated by it. An annular recess 6| Fig. 3) is formedin the base of the sock 5|, and nipples 62 projecting into this recessenclose the lower ends of the wires 60. With the construction describedan effective enclosing structure for the vibrator is provided which isvery simple in construction and embodies only a single and unitarytubular sock as distinguished from the two-part constructions which havebeen heretofore ordinarily utilized. The cost of such a molded rubbersock as that shown is about the same as that for one of the two partspreviously used so the cost is approximately halved.

In the operation of the vibrator it is connected in a circuitsubstantially like that of Fig. 6. Current is supplied from a lowvoltage direct current source, such as a storage battery 63, and thevibrator serves to interrupt the current so that it flows in impulsesthrough the primary winding 64 of a suitable step-up transformer 65,thereby inducing a high alternating potential in the transformersecondary winding 66. Upon closure of a starting switch 6'! current issupplied to the elec-- tromagnet energizing windings 38 (through acircuit 6168-38--69-4645|4-61) thereby causing the armature 2| to beattracted and swung upward (as viewed in Fig. 6) to close contacts Ill-lI. Closure of these latter contacts completes a circuit from the battery63 through the upper half of the transformer winding 64. Such movementof the reed and armature also opens the magnet contacts 45-46, however,so that the magnet is deenergized and the reed permitted to spring backin the opposite direction. This return movement of the reed reopens thecontacts IB-ll and closes the other set of'maln contacts l2 l3. Closureof these latter contacts completes a circuit from the battery 63 throughthe other half of the transformer primary winding 64. Also, on thereturn movement of the reed the magnet contacts 45-45 are reclosed sothat the magnet is reenergized and the cycle of contact closing andopening is repeated and continued with great rapidity.

The periodicity of reed vibration is his large measure dependent uponthe natural frequency of vibration of the reed itself, and in mostvibrators at the present time the reed is arranged to vibrate at a speedof approximately to cycles per second. The improved electromagnet andamature arrangement heretofore described aids materially in impartingstrong impulses to the armature for vibrating the reed, as washeretofore noted. Moreover, the device operates with a very small amountof mechanical noise because of the type of frame structure employed. Inparticular, a frame made of molded dielectric material is less resonantthan a frame made of steel or such materials which have been previouslyemployed so that it absorbs or dissipates much 0! the mechanicalvibratory forces in the device which would otherwisebe transmitted fromit in the form of sound waves in the surrounding air. The magnetcontrolling contacts 45-46 'whieh have heretofore been the source of alarge amount of clicking noise are particularly well isolated since anyvibrations set up by them in the structure must be transmitted throughthe entire body of the frame and, consequently, little or none of thesevibrations ever reaches the base portion of the enclosing sock throughwhich they would have to pass to reach the outer casing. In

general, it will be seen that a very much improved form of vibrator hasbeen provided which embodies a number of features that contribute verymaterially not only to a reduction in cost but also to improvement ioperating characteristics.

Although a preferred embodiment of the invention has been illustratedand described in some detail there is nointention thereby to limit theinvention to such preferred embodiment but on the other hand, "theappended claims are intended to cover all modifications and alternativeconstructions within the spirit and scope of the invention.

I claim as my invention:

1. A vibrator embodying a stack of lamination parts including a reed, apair of contact fingers on opposite sides thereof and electricalinsulating laminations interposed between adjacent end portions thereof,said vibrator being characterized by the inclusion of a supporting framefor said stack made of dielectric material and having an integralprojection thereon contacting both said reed and said contact fingers insaid stack for locating the same in predetermined relation with respectto each other.

2. A vibrator embodying a cantilever type vibratory reed with anarmature on the free end thereof, and a cooperating actuating magnetlocated close-to but entirely out of the path of said reed and armature,said electromagnet presenting to the extreme end face of said armature apole piece located beyond the same and with a predetermined clearancetherebetween longitudinally of the reed, said vibrator beingcharacterized by the inclusion of a supporting frame madeO of dielectricmaterial and to one end portion of which said electromagnet is fixed andon the opposite end portion of which is provided .an integral projectionengageable with said reed for locating the latter longitudinally withrespect to saidframe and with said predetermined clearance between saidarmatureand pole piece.

3. A' vibrator comprising, in combination, a frame made of moldeddielectric material and including an elongated side member with anintegral laterally facing pedestal on one end thereof having aprojection on the face thereof, a flat cantilever type vibratory reeddisposed with one side of the butt end portion thereof overlying theface of said pedestal and with the free end thereof extending toward theopposite end of said side member, means including an actuatingelectromagnet for vibrating said reed, said electromagnet embodying amagnetizable pole piece embed-' ded in fixed position in the moldeddielectric material adjacent said opposite end of said frame 'sidemember and disposedwith an active face thereof presented to' the outerend portion of said reed; and said reed having an. aperture thereinregistering with said projectionon said pedestal for locating said reedon said framewith respect to said pole piece.

4. A vibrator comprising, in combination, a frame made'of moldeddielectric material and including an elongated side member witlf anintegral laterally facing pedestal on one end there'of, said pedestalhaving apair of projections on the face thereof spaced apart withrespectto each other transversely of the pedestal face, a flat cantilever typevibratory reed disposed with one side of the butt end portion thereofoverlying said face of said pedestal and with the free end thereofextending toward the opposite end of said side member, an armaturecarried on the free end of said reed, an actuating electromagnetcooperating with said armature to vibrate said reed, said electromagnetembodying a magnetizable pole piece in the form of a pin embedded infixed position in the molded dielectric material adjacent said oppositeend of said frame side memher and disposed in generally longitudinalalinement with said reed and with the inner end thereof presented to theouter end of said armature in closely spaced relation thereto, and saidreed having notches fashioned in the side edges of the butt, end portionthereof dimensioned to receive said projections on said pedestal facefor locating' said reed and the armature thereon with respect to saidpole piece.

5. A vibrator embodying a plurality of structurally separate partssecured together as a unit and including a supporting frame, a vibratoryreed and a resilient sheet metal contact finger, said vibrator beingcharacterized by the provision of interfitting portions on said partsand including a dielectric projection on said frame part engageable withall of said other parts for locating the same in predetermined positionwith respect to each other in the assembly.

6. A vibrator embodying a plurality of struc turally separate partssecured together as a unit and including a supporting frame with anelectromagnet ilxed thereon, and a vibratory reed-with an armature fixedthereon for cooperation with said electromagnet, said vibrator beingcharacterized by the provision of an aperture in said reed and aninterfltting dielectric projection on said frame for locating said reedin predetermined position on said frame and with respect to saidelectromagnet during assembly of the unit.

II. A vibrator embodying an elongated frame and a substantially freelyvibratory cantilever reed fixed to one end'of said frame and extendingtoward the other end thereof, as well as a plurality of make and breakcontacts arranged to be actuated by the vibratory movement of said reed,characterized by the provision of an elongated pole piece fixed to saidother end of said frame and projecting outwardtherefrom with the majorportion thereof free of any confinement by the frame and in generallongitudinal alinement with the reed and accurately spaced with a smallclearance from the' free end of the reed, and an energizing coilencircling the projecting portion of said pole piece, whereby the coilmay be wound on the pole piece after the latter has been accurately andpermanently fixed in position on said frame.

8. A vibrator comprising, in combination, a frame made of moldeddielectric material with at least a portion thereof arranged insubstantially'a c-shape, a generally upright vibratory cantilever reed.having one end thereof fixed to one leg of the c with the free endthereof disposed closely adjacent the inner face of the other leg of the0, a magnetizable pole piece in the form of a pin embedded in the moldeddielectric material of said other leg with the inner end thereof on theprojecting portion of said pole piece.

9. A vibrator comprising, in combination, a frame made of moldeddielectric material with at least a portion thereof arranged insubstantially a C-shape, a generally upright vibratory cantilever reedhaving one end thereof fixed to one leg of the C and with the free endthereof disposed closely adjacent the inner face of the other leg of theC, a magnetizable pole piece in the form of a pin embedded in the moldeddielectric material of said other leg with the inner end thereof locatedclosely adjacent the free end of said reed and with the outer endthereof projecting freely beyond the end of the frame arm and in generallongitudinal alinement with the reed, a fiat piece of material securedto the outer end of said pin to form a spool end thereon opposed inspaced relation to the outer face of said other frame arm, and anenergizing winding spooled on said pin. i

10. A vibrator comprising, in combination, a frame made of moldeddielectric material and including an elongated side member with anintegral laterally facing pedestal on one end thereof, a cantilever typevibratory reed having the butt end portion thereof fixed to saidpedestal and extending toward the opposite end of said side member, anarmature carried by the free end of said reed, a magnetizableelectromagnet p-ole piece in the form of a pinembedded in the moldeddielectric material at said other end of said frame and disposed ingenerally longitudinal alinement with-said reed, the inner end of saidpin being disposed in closely spaced relation with said armature and theouter end portion of said pin being free of obstruction by said frame,an energizing winding on the outer portion of said pole piece pin, agenerally U-shaped portion of magnetizable metal fashioned as a stampingfrom sheet metal and having the bottom of the U fixed to the outer endof said pole piece pin and with the side arms thereof embracing thesides of said winding and projecting in operative relation with saidarmature.

11. A vibrator comprising, in combination, an elongated supporting framemade of non-magnetic cast material-and provided with an integraltransverse member at one end thereof, a cantilever type vibratory reedfixed to the opposite end of said frame and extending toward said oneend thereof, an'armature extending transversely across the free end ofsaid reed, and an actuating electromagnet for said armature, saidelectromagnet including a pole piece structure embodying a U-shapedstamping of resilient magnetizable metal facing toward the free end ofsaid reed with the arms of the U located opposite the ends of saidarmature in closely spaced relation thereto, said U-shaped piece ofresilient metal being disposed to embrace said transverse member on saidframe with the arms of the U resiliently pressed against the same tospace them accurately from the ends of the armature.

12. A vibrator comprising, in combination, a frame made of moldedmaterial and including an elongated side member with an integrallaterally facing pedestal on one end thereof, a fiat cantilever typevibratory reed disposed with one side of the butt end portion thereofoverlying the face of said pedestal and fixed thereto, the free end ofsaid reed extending toward the opposite end of said side member", acontact finger extending along one side of said reed and also fixed tosaid pedestal, an armature carried on the free end of said reed, meansincluding an actuating electromagnet cooperating with said armature tovibrate said reed, said electromagnet embodying a magnetizable polepiece in the form of a pin embedded in fixed position in the moldedframe material adjacent said opposite end of said frame member anddisposed in generally longitudinal alinement with said reed andprojecting away from the free end thereof, said electromagnet alsoincluding a generally U-shaped stamping of magnetizable metal fixed tothe outer end of said pin and with the arms thereof projecting along thesides of said pin in spaced relation thereto and into operative relationwith said armature to form additional electromagnet pole pieces, saidstamping also including an integral ear projecting toward said reed, asecond contact finger carried by said ear and projecting toward saidreed, and cooperating contacts carried by said reed and respectivecontact fingers. I

13. A vibrator comprising, in combination, an elongated supporting framemade from molded dielectric material, a cantilever type vibratory reedfixed to one end portion of said frame and extending along the same, anarmature carried by said reed, an actuating electromagnet for saidarmature carried by said frame at a point spaced from said one endportion and including an energizing winding, and a lead wire for saidwinding, said frame being fashioned with integral and longitudinallyextending reenforcing ribs on the outer surface thereof adapted toreceive said lead wire therebetween.

14. A vibrator comprising, in combination, a vibratory cantilever typereed having a generally rectangular armature fixed to the free endthereof, contact means arranged to be actuated by said reed in thevibratory movement thereof, and an actuating electromagnet for saidarmature disposed close to but entirely out of the path of movement ofthe latter, said electromagnet embodying a U-shaped pole piece structurewith a central core projecting through the middle of the Ulongitudinally thereof and arranged generally longitudinally of saidreed, said, central core being displaced from the idle position ofvibratory cantilever type reed having a generally rectangular armaturefixed to the free end thereof, contact means arranged to be actuated bysaid reed in the vibratory movement thereof, and an actuatingelectromagnet for said armature disposed close to but entirely out ofthe path of movement of the latter, said electromagnet embodying aU-shaped pole piece structure with a central core projecting through themiddle of the U longitudinally thereof and arranged generallylongitudinally of said reed, said central core being displaced from theidle position of said armature in the direction of initial movementthereof resulting from the energization of said electromagnet, thecross-section of said core being hexagonal in form with a face of thehexagon toward said armature, the side arms of said U-shaped pole piecestructure being arranged to project past the opposite ends of saidarmature in closely sulating laminations interposed thereloetween,-

spaced relation thereto but displaced from the idle position thereof inthe direction of said initial movement, said displacement being lessthan that of said core, and said electromagnet also including anenergizing winding encircling said core. I

16.'A vibrator embodying a stack oi, generally laminated parts securedtogether as a unit, and.

including a vibratory reed with contact fingers located adjacentopposite sides thereof and inanodes? said vibrator being characterizedby the provision of electric terminals projecting laterally from thesides of said stack in spaced relation to each other transversely of thestack and electrically connected to individual elements of the stackstructure so that the vibrator assembly may be readily inserted in atest receptacle or the like to connect test circuits to said terminals.

EDWARD L. BARRETT.

